Unify constraint options in all migrations

[kvch]

Now that the constraints in create_table contain all of the possible settings for constraints, we can go ahead and reuse the same writers and provide the same options for create_constraint and column level operations.

• primary key
  • new type in create_constraint New constraint type in create_constraint: primary_key #698
  • breaking change: add support for index parameters in inline definition
• unique
  • breaking change: support index parameters
• deferrable column level constraints
• exclusion constraint [feature request] exclusion constraints #677
• check: Add support for no_inherit on column level constraints and in create_constraint operation #670
• foreign key: Expose foreign key constraint options in inline FK definition and in create_constraint #653

[kvch]

At the moment we cannot support adding primary key constraints to (any) existing tables properly because pgroll does not support backfilling tables that does not have a PK (or a unique column).